More Lung Tests Improve Lung Function in CF Youth: Study

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by Steve Bryson, PhD |

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More frequent lung function tests in young people with cystic fibrosis (CF) markedly increased the diagnoses of pulmonary exacerbations — bouts of lung symptom worsening — leading to improved treatment and better lung function, a Brazilian study suggested.

“The impact of such a simple initiative can be substantial and even more relevant in countries such as Brazil, with reduced treatment resources and financial constraints,” the researchers wrote.

The study, “Routine spirometry in cystic fibrosis patients: impact on pulmonary exacerbation diagnosis and FEV1 decline,” was published in the Brazilian Journal of Pulmonology.

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In CF, the lungs are compromised due to the buildup of thick mucus, which increases the risk of tissue-damaging infections. Pulmonary exacerbations — a rapid worsening of lung symptoms — have a major impact on the decline of lung function, quality of life, and long-term survival.

Lung function tests (spirometry), including FEV1, the amount of air forced from the lungs in one second, are routinely used to diagnose exacerbations.

Although routine FEV1 tests at all clinical visits are recommended for CF patients in some countries, this practice is not universally adopted in developing countries with limited technical and financial resources.

Researchers at the University of São Paulo in Brazil wondered whether more frequent FEV1 tests influence the diagnosis of pulmonary exacerbations and improve long-term lung function.

To find out, the team followed for one year a group of 80 CF patients, ages 5 to 18, who underwent routine FEV1 tests every two months. They then compared pulmonary exacerbation data to their medical records from the previous two years, in which FEV1 was given every six months.

During the one-year follow-up, there were 418 clinical visits, with an average of 5.2 visits per patient. Pulmonary exacerbations were diagnosed in 27.5% of the visits (115 occasions), with an average frequency of 1.44 exacerbations per patient/year.

This frequency of exacerbations was significantly higher than that observed two years before, 0.88 exacerbations per patient, but slightly higher than one year earlier, at 1.15 exacerbations per patient.

These findings demonstrated that “performing spirometry at each encounter has a significant impact on the diagnosis of [pulmonary exacerbations] during the outpatient management of CF patients,” the team wrote.

Most (85%) of pulmonary exacerbations were treated with oral antibiotics, while some (5%) received inhaled antibiotics, with or without oral antibiotics. Hospitalization for intravenous (into-the-vein) antibiotics occurred in 10.4% of cases.

The attending physician cited the FEV1 test as a method used to diagnose pulmonary exacerbations in 83.5% of the cases. In 21.9% of those diagnosed with an exacerbation, the decision to start antibiotic therapy was exclusively defined by a decline in FEV1. In comparison, on about 9% of occasions, physicians reported lung function tests excluded a diagnosis of pulmonary exacerbation.

During follow-up, the median percent predicted FEV1, defined as FEV1 of the patient compared with the average FEV1 for any person of similar age and sex, was 85.7%. In comparison, two years before it was 76.9% and in the previous year, 78.5%. These differences were not statistically significant.

Additional FEV1 data were assessed from the two years after the one-year follow-up. Although there was a slight, steady decline in FEV1 results after the initial follow-up, about 2% per year, they remained above 80% in the two following years.

“Spirometry was also associated with a meaningful increase in lung function,” the team added.

“These findings reinforce the recommendations of several guidelines that spirometry be performed at each patient encounter and also indicate that recognising and treating [pulmonary exacerbation] more often results in better lung function for CF patients,” the researchers wrote. “Further studies could be of value to identify other aspects that impact lung function in CF patients in Brazil.”